Elasticsearch Keystore Authentication Failure

[Aidan_Li]

I have a GCP bucket, and machines running with ES 7.6.1 in two separate clusters:

• cluster 0, with machines "machine 0"
• cluster 1, with machines "machine 1"
• GCP Bucket

My goal is:

1. register a repository with this GCP Bucket on machine 0
2. snapshot to this bucket with machine 0
3. register a repository with this GCP Bucket on machine 1
4. restore from the snapshot created by machine 0

For both machines, I have:

1. installed repository-gcs
2. added the credentials to ES: elasticsearch-keystore add-file gcs.client.default.credentials_file <service_account.json>
3. POST localhost:9200/_nodes/reload_secure_settings to reset the secure settings.
4. Restart ES (only necessary on older versions of ES, but I tried it anyway)

From there I am able to:

1. Register a repository with this GCP Bucket on machine 0
2. Snapshot to the bucket
3. Restore from this snapshot back to machine 0

However, I am not able to register, snapshot, or restore following the exact same steps on machine 1. I have tried at least 10 times on multiple different machines from each cluster and am able to reliably interact only with machines from cluster 0.

For machines from cluster 1, I get this authentication error:

curl -X PUT "localhost:9200/_snapshot/test-backup?pretty" -H 'Content-Type: application/json' -d'
> {
>   "type": "gcs",
>   "settings": {
>     "bucket": "<bucket>",
>     "base_path": "backup"
>   }
> }
> '
{
  "error" : {
    "root_cause" : [
      {
        "type" : "blob_store_exception",
        "reason" : "Unable to check if bucket exists"
      }
    ],
    "type" : "repository_exception",
    "reason" : "[test-backup] cannot create blob store",
    "caused_by" : {
      "type" : "blob_store_exception",
      "reason" : "Unable to check if bucket exists",
      "caused_by" : {
        "type" : "security_exception",
        "reason" : "access denied (\"java.lang.RuntimePermission\" \"accessDeclaredMembers\")"
      }
    }
  },
  "status" : 500
}

On machines from cluster 1, I can even access the bucket using gsutil, so I don't believe it's a network configuration issue.

I am completely out of ideas as to why two machines, with the same version of ES, configured the same way with elasticsearcy-keystore with the same service account would behave differently in this scenario.

Any suggestions would be greatly appreciated.